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Free keywords:
millipedes; seasonality; inundation; floodplains; Amazon; Neotropics
Abstract:
Pycnotropis tida (Chamberlin, 1941) (Diplopoda, Aphelidesmidae) inhabits mixed- and whitewater inundation forests from the upper to the central Amazon Basin (Nauta/Peru-Manaus/Brazil) as well as a non-flooded upland forest at Manaus. This polydesmidan species is capable of populating inundation forests despite the adverse living conditions i.e., annual flooding of up to 7 months duration and low relative humidity on the bark of tree trunks, where adults pass the aquatic phase. The development of immature stadia takes 7 months and therefore P. tida cannot inhabit forests with more than 5 months flooding. Fresh weight in adult P. tida varied, depending on the collection site (inundation and upland forests). Females were generally heavier than males. In the laboratory, longevity in adults from an upland forest was higher compared to animals from inundation forests, regardless of both temperature and sex. The highest number of mature eggs, monitored in females of inundation forests throughout the year, was found at the end of the aquatic phase (n less than or equal to 605). Highly variable numbers of eggs and and ovipositions reflect the instability of the environment. The seasonal phenology observed in the univoltine P. tida from inundation forests is caused by the flood pulse,: as the juveniles cannot survive or escape flooding. The populations from non-flooded upland forests are plurivoltine, with terricolous immatures and adults occurring throughout the year. The origin of P tida in seasonal upland forests of the Western Andes and its propagation downstream of the Solimoes/Amazon River is discussed.
